BURNABY, British Columbia — Xenon Pharmaceuticals Inc., a clinical-stage biopharmaceutical company, today announced the initiation of a Phase 1 clinical trial of its proprietary epilepsy product candidate, XEN901, which is an orally administered, small molecule, highly selective Nav1.6 sodium channel inhibitor. The Clinical Trial Application (CTA) for XEN901 was accepted by the Medicines & Healthcare products Regulatory Agency (MHRA) in the United Kingdom (UK), and the first subject has now been dosed in the Phase 1 clinical trial.

XEN901 is a potent, highly selective Nav1.6 sodium channel inhibitor being developed by Xenon for the treatment of epilepsy, including treatment resistant adult and pediatric focal seizures, as well as rare, pediatric forms of epilepsy, such as EIEE13, an early infantile epileptic encephalopathy associated with gain-of-function mutations in the SCN8A gene, which encodes the Nav1.6 sodium channel.

Dr. Simon Pimstone, Xenon’s President and Chief Executive Officer, said, “With the initiation of the XEN901 Phase 1 clinical trial, Xenon now has two anti-epileptic therapeutics in clinical development, each highly validated and with novel mechanisms of action. We believe this further supports our efforts to become a leader in the development of therapeutically differentiated alternatives to the anti-epileptic medications currently available, and we believe that XEN901 is the only selective Nav1.6 inhibitor currently in clinical development. Non-selective sodium channel inhibitors are broadly used for the treatment of focal seizures but are limited by their narrow therapeutic window. We anticipate that XEN901, as a highly selective Nav1.6 inhibitor, could offer an efficacious treatment with a better therapeutic index due to its improved target selectivity.”